Most vehicle side doors include a window that is movable vertically between a lower open position and an upper closed position while passing through partially open positions of varying extents. Such window movement is normally controlled by either a manual or power operated window regulator. With many sedan type vehicles, the side door has a frame that defines a window opening corresponding to the perimeter of the side door window at its front, top, and rear edges. Such window frames conventionally have a groove that receives the front, top, and rear edges of the window to provide positioning of the window in the upper closed position. Vehicle side doors without window frames are also manufactured for use with hardtop, convertible, T-top, and other vehicle designs wherein it is desirable not to have any window frame.
U.S. Pat. Nos. 4,399,600 and 4,567,636 disclose vehicle door conversion that permits a vehicle door of the type having a window frame to be converted to a frameless type door. Such conversion greatly enhances manufacturing flexibility by permitting vehicles of both the framed and frameless side door window type to be manufactured on the same assembly line with a station where window frame removal is performed depending upon which type of vehicle is desired.
Vehicle body designs for the past twenty years or so have incorporated side door windows having "tumble-home", which is inboard curvature in an upward direction above the side door in which the window is stored in the lower open position. Such tumble-home curvature makes sealing of frameless side door windows more difficult since it is not as easy to control the location of the top edge of the window as can be done with framed side door windows. This is especially true when the side door is of the frameless type converted from a frame type wherein the window regulator mechanism is designed to cooperate with the window frame in positioning the window in the upper closed position.